Document desired behavior for fiber::thread_affinity().
Also clarify Preconditions for fiber::priority().
Document new [un]bounded_queue API, plus a bit of guessing.

Change certain [un]bounded_queue method signatures to return queue_op_status.
Their previous signatures didn't provide any way to report a closed queue.
For Note: interruption point, document Throws: fiber_interrupted.
Write a few more words about bounded_queue's high water mark and low water
mark.
Document that bounded_queue constructor can in fact throw.
Describe this_fiber::thread_affinity() in terms of fiber::thread_affinity().
Also mention that fiber::thread_affinity() is off by default.
Fix markup error in fiber::thread_affinity() Note.
Start adding internal cross-references to fiber documentation
Link this_fiber::thread_affinity() to fiber::thread_affinity().

Use [#named_anchor] QuickBook functionality rather than trying to predict the
normalized link for [heading Member function `thread_affinity( bool)`], which
looks like this:

fiber.fiber_mgmt.fiber.member_function__code__phrase_role__identifier__thread_affinity__phrase__phrase_role__special_____phrase___phrase_role__keyword__bool__phrase__phrase_role__special_____phrase___code_
Merge pull request #5 from nat-goodspeed/fiber-mt

Fiber mt